H3-12.0-Smart Modbus Connection

[Mabu77]

Hello, my system has been running for about 14 days now, and I am not very satisfied with the connection to Home Assistant via the cloud. I have now purchased a Modbus gateway for this purpose. Earlier today, I unscrewed the plug for the meter to check how much effort the cabling would require. I noticed that this connection is done with a LAN connection on the inverter. Other then expected. The smart meter (which is unfortunately not correctly connected to the grid) is already connected there with the LAN cable. I haven't found anything about this online yet. Can I assume that the wires on pins 1 and 2 are the correct ones? Has anyone else connected it this way before?

Best regards
Marc

[Dave Foster]

I assume when you say LAN cable, that they've used cat5 cable and it isn't an ethernet RJ45 plug ?.

I think you are looking at the meter connector and on the H3 Smart the RS485 pins for the computer have been moved to the much larger 'COM' connector and they have called them EMS 485A/B - those are the pins you need to connect to.

[Mabu77]

You mean this one?

[Dave Foster]

No that's where the datalogger plugs in and Fox have un-helpfully labelled it the COMM/Dongle port

This is the COM port

And these are the pin outs for it.

[Nelbjo]

Hi all,
Please let me jump onto this topic.
My new H3-10.0-Smart inverter gets installed today and I would like to set up modbus for Homeassistant and EVCC.

I have purchased an elfin W11a and understood that this needs to be connected to the ems485a/b ports of the com connector.
However, which pins do I need to connect the 12V power +/- ?

A second question: EVCC integration for the H3-smart also list „modbus tcpip“ option.

# Modbus TCP
modbus: tcpip
id: 247
host: 192.0.2.2 # Hostname
port: 502 # Port

Does this mean the RS485 dongle ist not needed to set the H3-smart up in EVCC?
Does this only work for EVCC or also for home assistant?

Thanks for your comments.

[Mabu77]

Hi,

I connected a serial/LAN adapter with an external power supply. One from the big A. USR-TCP232-304 works fine for me.

The option to attach the Fox inverter directly with the ip doesn´t work for me. And as far as i understood there is no option - at the moment - to connect with homeassitant directly to the inverter.

BR
Marc

[Nelbjo]

Hi Marc,

Thanks for your feedback.
I have got a RS485 to wifi adapter.
I guess you connected yours to an external 12V DC power supply?

I know that the H3 inverters had the option to use a built-in 12V connection to supply the RS485 adapter. I am now wonder which ports of the com dongle of the H3-smart to use to connect to 12V.

In the screenshots above, there is a +12V port (#12). I wonder if this plus one GND port are the correct ones.

[Dave Foster]

In the screenshots above, there is a +12V port (#12). I wonder if this plus one GND port are the correct ones.

There is 12v out on the connector which is used to power the Fox EMS unit, it's not very powerful, we believe around 300mA max current - most people use an external 12V 1A power supply as the Elfin can be a little fussy about it's power source (don't forget with RS485 pairs the Elfin can be wired some distance away from the inverter if you use good quality shielded cable ~cat5/6 which might make finding power easier).

[Nelbjo]

Thanks for the good info. OK - then presumably it’s better to get an external power supply.

I intended to use an old USB cable for connection. I still have plenty of cat 6e installation cable (the orange one with solid wires) - can I use that one for the RS485 connection?

[Dave Foster]

Thanks for the good info. OK - then presumably it’s better to get an external power supply.

I intended to use an old USB cable for connection. I still have plenty of cat 6e installation cable (the orange one with solid wires) - can I use that one for the RS485 connection?

I've never used the Elfin myself but a few years back there were a number of people that used the USB power that was on the Gen 1 inverters, it didn't work well and so they went to a distinct power supply - there's obviously no harm in trying it but you'll need to keep the Elfin in an enclosure nearby and I do know they don't like extreme cold, if you can run a longer cable and use a good power supply i'd do that.

No problem using Cat 6e but make sure you use a 'pair' i.e. orange and orange/white, some installers have used 2 pairs one pair for each core but that doesn't give you the common mode noise rejection a single pair does.

[Nelbjo]

Thanks Dave, excellent.
So if understood correctly you recommend I use only one twisted pair?: e.g.
- orange for 485A
- orange/white for 485B

[Dave Foster]

Thanks Dave, excellent.
So if understood correctly you recommend I use only one twisted pair?: e.g.
- orange for 485A
- orange/white for 485B

Yes that's it, it doesn't matter which pair you use as long as you use a twisted pair (i.e. single color & same colour with white stripe)